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All the employees

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All the employees

by CrackGMAC » Thu Aug 27, 2009 8:12 am
129. All the employees in a company are more than 20 years old. Is the average age of all employees more than 35?
1). 50% of employees are more than 40 years old.
2). 25% of employees are more than 60 years old.

IMO C. Average age will definately be greater than 20
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by GambitOS » Thu Aug 27, 2009 10:06 am
Let's
a. 50%=2*40 y.old
b. 25%=60 y.old

For example, ((2*40)+60+x(we can take the lowest - 20))/4=160/4=40

So we need a & b to solve this problem, but I thing this is the problem from DS.
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Must be C

by enniguy » Fri Aug 28, 2009 5:27 am
It must be C.Whats the OA?

Consider 100 people in the company.

A - 50% are aged above 40 years. i.e: 50 are above 40 years. Let's assume the rest 50 are 20 years old (Minimum possible from the question).

Total Age / Total number = 3000/100 = 30. So, Avg age Above 30 years. NOT SUFFICIENT.

B - 25% are aged above 65. Calculating similarly as above,
Total = 25*60 + 75*20 = 3000. Avg = 3000/100 = 30.

Together, 25% above 60 years, Another 25% above 40 years. Remaining 50% 20 years.

Total = 25*60 + 25*40 + 50*20
= 1500 + 1000 + 1000 = 3500.

Avg = 35. SUFFICIENT.
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by CrackGMAC » Fri Aug 28, 2009 7:51 am
Thanks for help. I don't have the ans but I am confident its C. Do we get these small little question in GMAT?
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by heshamelaziry » Fri Aug 28, 2009 10:21 am
CrackGMAC wrote:Thanks for help. I don't have the ans but I am confident its C. Do we get these small little question in GMAT?
To me, this is not a little question. I f you find this easy, cheer up, the test is full of them.
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Re: Must be C

by heshamelaziry » Fri Aug 28, 2009 10:30 am
enniguy wrote:It must be C.Whats the OA?

Consider 100 people in the company.

A - 50% are aged above 40 years. i.e: 50 are above 40 years. Let's assume the rest 50 are 20 years old (Minimum possible from the question).

Total Age / Total number = 3000/100 = 30. So, Avg age Above 30 years. NOT SUFFICIENT.

B - 25% are aged above 65. Calculating similarly as above,
Total = 25*60 + 75*20 = 3000. Avg = 3000/100 = 30.

Together, 25% above 60 years, Another 25% above 40 years. Remaining 50% 20 years.

Total = 25*60 + 25*40 + 50*20
= 1500 + 1000 + 1000 = 3500.

Avg = 35. SUFFICIENT.
If hte question says "more than 20 years old", why you assume that employees are 20,40, or 60 ????
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Re: Must be C

by enniguy » Fri Aug 28, 2009 4:50 pm
heshamelaziry wrote: If hte question says "more than 20 years old", why you assume that employees are 20,40, or 60 ????
I am assuming the least possible for every case.
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Re: Must be C

by heshamelaziry » Fri Aug 28, 2009 5:11 pm
enniguy wrote:
heshamelaziry wrote: If hte question says "more than 20 years old", why you assume that employees are 20,40, or 60 ????
I am assuming the least possible for every case.
Ok. I just thought of this:

If choice A reveals average age 30 and choice B reveals average age of 30, then each statement alone is Sufficient.

Please,advise.
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by heshamelaziry » Fri Aug 28, 2009 5:13 pm
CrackGMAC wrote:Thanks for help. I don't have the ans but I am confident its C. Do we get these small little question in GMAT?
If choice A reveals average age 30 and choice B reveals average age of 30, then each statement alone is Sufficient. We only need to answer the question By either YES or No.
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by heshamelaziry » Sat Aug 29, 2009 1:44 pm
According to the solution. OA should be D. Each statement alone is sufficient, because each gives the answer to be NO.
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by pathaniaus » Sun Aug 30, 2009 5:52 am
I think it should be C.

Sample size = 100.

1) 50% > 40 yrs old -
Age = 41, and 21 (b/c, >40 and >20)
[50(41)+50(21)]/100 = 31. 31 < 35 which means that the avg age could be above OR below 35. INSUFFICIENT

2) 25% > 60 yrs old -
Age = 61 and 21
[25(61)+75(21)]/100 = 31. 31 < 35. same situation as above. INSUFFICIENT

1) & 2) - [50(41) + 25(61) + 25(21)]/100 = 41. SUFFICIENT, b/c we used the minimum age for each given piece of info.

therefore, C.

Maybe I'm wrong. I don't understand why you say D. Please explain.
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by CrackGMAC » Fri Sep 04, 2009 3:21 am
C it is!!!
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by tom4lax » Fri Sep 04, 2009 5:46 pm
Use weighted averages:

1) .5*40 + .5*20 = 24 insufficient
2) .25*60 + .75*20 = 30 insufficient

combined .5*40+.25*60+.25*20=40 sufficient
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